I already installed lab in Gmail which puts the chat list to the right side to have more space.

Now I'd like to group the contacts in the online list in any grouping, best would be the same as Gmail contact groups (or less relevantly maybe Circles), actually anything semantic (i.e. not grouped by first letter or similarly useless).

Can anyone point me a Lab, Greasemonkey script or something similar to achieve this?

Edit: use cases (may be imaginary) (as suggested by @OnenOnlyWalter)

The general idea is that everywhere you can group stuff to organize and work more effectively, easily: think about Contact Groups, Circles, Facebook friend groups (lately even created automatically (Smart lists) for your convenience), Skype contact groups, MSN contact groups, ... I think you get the idea.

Now let's see some scenarios:

At work we use Google Apps hence Gmail, Talk, Drive, ... I work for support and I support at least 5 customers at time. Each customer has it's own team within the company. I added them to my Contacts and grouped them by team. I want to be able to see who is online from a given team because I need to ask a quick question / remember the client may be on the line...

I have my family, friends, colleagues, sport-mates and I want to have see their statuses, but when I want to see if someone is online to ask to go play Squash I don't want to filter my family members/colleagues with my eye if I could just close those groups.

Remember a time when the Labels in Gmail were flat, i.e. no hierarchy? What about now? Different [custom] colors, "infinite" nesting, all out of the box. There were Labs and scripts making it possible then it got integrated. I know there are workarounds for everything, for example on Skype I renamed all my contacts to include prefixes in their names, because it has contact groups, but you can only see one group at a time.
Of course when I know who I want to talk to I can filter by typing, however most people like clicking more.

In the end it all comes down to convenience, effectiveness, customization.
As a strong example: you can use telnet to send Emails through SMTP with hand-written XHTML and Base64 encoded image attachments, why do you use a modern browser, Gmail and its rich text editor then?

I've been searching for it but it's really hard, because everything is called 'group': GMail contact groups; Group chat in GMail/Google Talk; Google Groups mailing lists
–
TWiStErRobAug 28 '12 at 14:41

Why are trying to group the chat contacts? If you can explain the use case here it might help. Is it just that the list of contacts is too long? Can you not just start typing a persons name in the chat search to pull their information card?
–
OnenOnlyWalterOct 16 '12 at 17:11

1

To add to this, let's say in my office we have 100 people on chat. On my team I have 5 and on our floor 20. I'd like to group those 5 into a TEAM group, have them listed at the very top of my buddy list, etc. if there's a work around, I'm open.
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user63184Mar 13 '14 at 16:58